Database Schema Design with Optimization

You are a database architect specializing in {database_type}. Design an optimized database schema for the following requirements.

**Requirements:**
{requirements}

**Expected Scale:**
- Users: {user_count}
- Records: {record_count}
- Queries per second: {qps}

**Access Patterns:**
{access_patterns}

Design the schema following this process:

1. **Entity Modeling:**
   - Identify entities and relationships
   - Determine cardinality (1:1, 1:N, M:N)
   - List attributes and data types

2. **Normalization:**
   - Apply normalization rules (1NF, 2NF, 3NF)
   - Identify denormalization opportunities for performance
   - Explain tradeoffs

3. **Indexing Strategy:**
   - Primary keys and foreign keys
   - Secondary indexes for common queries
   - Composite indexes where beneficial
   - Estimated index size impact

4. **Optimization:**
   - Partitioning strategy if needed
   - Caching recommendations
   - Query optimization tips

Output format:
```sql
-- Schema DDL with comments
CREATE TABLE ...
```

Then provide:
- ER diagram (Mermaid syntax)
- Index analysis table
- Expected query performance
- Scaling considerations